This invention pertains to adjustable beds or the like, and in particular to adjustable support frames therefor of the kind having a base upon which are surmounted a plurality of hinged-together, load-bearing sections forming, respectively, back, thigh, and foot rests.
Adjustable support frames of the foregoing kind are well-known to the art and each employ various types of mechanisms for adjusting the position of the load-bearing sections. An exemplary embodiment of such a frame is disclosed in Peterson, U.S. Pat. No. 3,230,554. Briefly, that patent discloses a supprt frame comprising a base having a back rest section hinged thereto. A thigh rest section is hinged at one end to the adjacent end of the back rest section, and a foot rest section is hinged at one end to the adjacent opposite end of the thigh rest section. A plurality of linking members are connected at one end to the base and at the opposite end to the thigh and foot rest sections to provide support therefor.
The elevating mechanism for adjusting the position of the load-bearing sections comprises a motor, connected to the base, having a threaded axle projecting therefrom which is threadably received by a collar connected to the back rest section.
Because the thigh and foot rest sections are connected to each other and to the back rest section, it is, of course, necessary that the linking members supporting the thigh and foot rest sections be movable in order to allow pivoting movement of the back rest section. Movement of the linking members is provided by hinging each of said members at one end to the base and at the opposite end to the load-bearing section supported by the member.
The primary drawback to frames of the kind just described resides in the fact that their primary degree of adjustability is with respect to the head rest section and only secondarily with respect to the remaining sections as the linking members shift to accommodate head rest section movement. No mechanism is provided for enabling the separate adjustment of the thigh and foot rest sections.
The prior art response to the foregoing drawback has been to incorporate a stationary load-bearing section intermediate the back and thigh rest sections, and then adding a second motor or the like to separately control adjustment of the thigh and foot rest sections. Such a support frame is disclosed in Draper, U.S. Pat. No. 2,996,732.
Insofar as the inventors herein are aware, the prior art has been unsuccessful to date in adapting the general concept disclosed in Draper to support frames of the kind disclosed in Peterson and to which this invention relates.
In view of the foregoing, it is a general object of this invention to provide a new and useful adjustable support frame having means therein for adjusting the position of the back rest section, as well as means for adjusting the position of the thigh and foot rest sections without affecting the positioning of the back rest section.
Still further, it is an object of this invention to provide a device of simplified construction which accomplishes the foregoing general object, thereby producing a device of reduced cost and increased mechanical reliability.